Lucien Hardy wrote:
> I would like to know if somebody can provide me a way to calculate
> the inverse Laplace transform (numeric) of discrete set of
> experimental point.
> In fact, I know it can be done for the Fourier transform (with the
> "ifft" function) and I would like to get the same but for inverse
> Laplace transform.
> Can anyone help with this, it would be of a GREAT help for me.
> Thans in advance.
> Lucien.

There is a small body of literature on this, much of it by Ward
Whitt and his co-authors. Seehttp://www.columbia.edu/~ww2040/B.html
for a list. If your experimental points are not regularly
spaced, you might need to interpolate so the inversion routine
can get regular samples. I don't think there's yet any
general-purpose Matlab code to do the inversion, unfortunately.

Andrew M. Ross wrote:
>
>
> Lucien Hardy wrote:
>> I would like to know if somebody can provide me a way to
> calculate
>> the inverse Laplace transform (numeric) of a discrete set of
>> experimental point.
>> In fact, I know it can be done for the Fourier transform (with
> the
>> "ifft" function) and I would like to get the same but for
inverse
>> Laplace transform.
>> Can anyone help me with this, it would be of a GREAT help for
me.
>> Thanks in advance.
>> Lucien.
>
> There is a small body of literature on this, much of it by Ward
> Whitt and his co-authors. See
> <http://www.columbia.edu/~ww2040/B.html>
> for a list. If your experimental points are not regularly
> spaced, you might need to interpolate so the inversion routine
> can get regular samples. I don't think there's yet any
> general-purpose Matlab code to do the inversion, unfortunately.
>
> Andrew
>
> --
> Andrew Ross
> Industrial and Systems Engineering (www.lehigh.edu/~inime/)
> Lehigh University
> Bethlehem, Pennsylvania, USA
> remove all digits <=4 from my e-mail address to reply
>
>

Hello Andrew,

Thanks a lot for your help. I have downloaded two papers on Laplace
inversion methods.
I will check them to see if I can write a matlab code (though job for
me as I am not an expert of matlab at all !).

Anyway, I find it quite odd that it is not included in Matlab because
the definition of both Laplace and Fourier transforms are very
similar (if I am not wrong) ...

Lucien Hardy wrote:
> Hello,
>
>
> I would like to know if somebody can provide me a way to calculate
> the inverse Laplace transform (numeric) of discrete set of
> experimental point.
>
>
> In fact, I know it can be done for the Fourier transform (with the
> "ifft" function) and I would like to get the same but for inverse
> Laplace transform.
>
>
> Can anyone help with this, it would be of a GREAT help for me.
>
>
> Thans in advance.
>
>
> Lucien.

Lucien,

I have sent you a paper with Matlab code in it. It is rather stable,
from my experience. Hope it helps.

In article <eebed25.-1@WebX.raydaftYaTP>,
"Lucien Hardy" <lhardy@chm.ulaval.ca> writes:
>Hello,
>
>
>I would like to know if somebody can provide me a way to calculate
>the inverse Laplace transform (numeric) of discrete set of
>experimental point.
>
>
>In fact, I know it can be done for the Fourier transform (with the
>"ifft" function) and I would like to get the same but for inverse
>Laplace transform.
>
>
>Can anyone help with this, it would be of a GREAT help for me.
>
if you find nothing in matlab directly, then netlib may help:http://www.netlib.org/toms
has the codes 619 , 662 and 682 for this. you may "mex" them.
hth
peter

You could try invlap.m from Karl Hollenbeck. (See below for the shortish
comments and reference).
Note however, that in this case you are required to specify a function F(s)
as an m-file.
I'm not sure exactly what you mean by "experimental points" for F(s).

"Lucien Hardy" <lhardy@chm.ulaval.ca> wrote in message
news:eebed25.-1@WebX.raydaftYaTP...
> Hello,
>
>
> I would like to know if somebody can provide me a way to calculate
> the inverse Laplace transform (numeric) of discrete set of
> experimental point.
>
>
> In fact, I know it can be done for the Fourier transform (with the
> "ifft" function) and I would like to get the same but for inverse
> Laplace transform.
>
>
> Can anyone help with this, it would be of a GREAT help for me.
>
>
> Thans in advance.
>
>
> Lucien.

DJL wrote:
>
>
> You could try invlap.m from Karl Hollenbeck. (See below for the
> shortish
> comments and reference).
> Note however, that in this case you are required to specify a
> function F(s)
> as an m-file.
> I'm not sure exactly what you mean by "experimental points" for
> F(s).
>
> David Wilson.

Hello David,

By "experimental points", I mean that the set of data points which
for I need to calculate the inverse Laplace transform is obtained
experimentally. More precisely it is a file containing two columns of
data, one for the abscissa and the other for the measured signal
itself.
Note that,in that particular case, the abscissa are "time", I know it
should be frequency as in common case but in that particular case it
is time.
I hope it does not matter as I see it to be regarded as a matter of
"convention".

Lucien Hardy wrote:
>
> DJL wrote:
> >
> >
> > You could try invlap.m from Karl Hollenbeck. (See below for the
> > shortish
> > comments and reference).
> > Note however, that in this case you are required to specify a
> > function F(s)
> > as an m-file.
> > I'm not sure exactly what you mean by "experimental points" for
> > F(s).
> >
> > David Wilson.
>
> Hello David,
>
> By "experimental points", I mean that the set of data points which
> for I need to calculate the inverse Laplace transform is obtained
> experimentally. More precisely it is a file containing two columns of
> data, one for the abscissa and the other for the measured signal
> itself.
> Note that,in that particular case, the abscissa are "time", I know it
> should be frequency as in common case but in that particular case it
> is time.
> I hope it does not matter as I see it to be regarded as a matter of
> "convention".

What do you intend the "inverse" Laplace transform of a time history to
represent?

Jinsong <jinsongliang@yahoo.com_nospam> wrote in message <b1Vpd89EGHgw@cc.usu.edu>...
> Lucien Hardy wrote:
> > Hello,
> >
> >
> > I would like to know if somebody can provide me a way to calculate
> > the inverse Laplace transform (numeric) of discrete set of
> > experimental point.
> >
> >
> > In fact, I know it can be done for the Fourier transform (with the
> > "ifft" function) and I would like to get the same but for inverse
> > Laplace transform.
> >
> >
> > Can anyone help with this, it would be of a GREAT help for me.
> >
> >
> > Thans in advance.
> >
> >
> > Lucien.
>
> Lucien,
>
> I have sent you a paper with Matlab code in it. It is rather stable,
> from my experience. Hope it helps.
>
> Regards,
>
> Jinsong
>

Hello Jinsong,

I'm really interested in this post. Could you send me too the matlab code to perform the inverse laplace transform of a discrete set of experimental points, please?

"Lucien Hardy" <lhardy@chm.ulaval.ca> wrote in message <eebed25.-1@WebX.raydaftYaTP>...
> Hello,
>
>
> I would like to know if somebody can provide me a way to calculate
> the inverse Laplace transform (numeric) of discrete set of
> experimental point.
>
>
> In fact, I know it can be done for the Fourier transform (with the
> "ifft" function) and I would like to get the same but for inverse
> Laplace transform.
>
>
> Can anyone help with this, it would be of a GREAT help for me.
>
>
> Thans in advance.
>
>
> Lucien.

Hello Luciend,

I'm really interested in this post. Could you send me the matlab code to perform the inverse laplace transform of a discrete set of experimental points, please?

I am searching for a Matlab Code/Function that can do t
he Laplace transformation for a numerical/experimental data.

Can anyone help me in this matter please?

Jad

"Eric " <eric.garcia@ucm.es> wrote in message <m161dn$kps$1@newscl01ah.mathworks.com>...
> "Lucien Hardy" <lhardy@chm.ulaval.ca> wrote in message <eebed25.-1@WebX.raydaftYaTP>...
> > Hello,
> >
> >
> > I would like to know if somebody can provide me a way to calculate
> > the inverse Laplace transform (numeric) of discrete set of
> > experimental point.
> >
> >
> > In fact, I know it can be done for the Fourier transform (with the
> > "ifft" function) and I would like to get the same but for inverse
> > Laplace transform.
> >
> >
> > Can anyone help with this, it would be of a GREAT help for me.
> >
> >
> > Thans in advance.
> >
> >
> > Lucien.
>
>
> Hello Luciend,
>
> I'm really interested in this post. Could you send me the matlab code to perform the inverse laplace transform of a discrete set of experimental points, please?
>
> Thank you very much in advance,
>
> Eric

"Lucien Hardy" <lhardy@chm.ulaval.ca> wrote in message <eebed25.-1@WebX.raydaftYaTP>...
> Hello,
>
>
> I would like to know if somebody can provide me a way to calculate
> the inverse Laplace transform (numeric) of discrete set of
> experimental point.
>
>
> In fact, I know it can be done for the Fourier transform (with the
> "ifft" function) and I would like to get the same but for inverse
> Laplace transform.
>
>
> Can anyone help with this, it would be of a GREAT help for me.
>
>
> Thans in advance.
>
>
> Lucien.

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